Comparative Leaf Blade Anatomy and Genetic Relationship by iPBS Marker of Clerodendrum L., Rotheca Raf. and Volkameria L. (Lamiaceae) in Thailand

Abstract

The comparative leaf blade anatomical study and genetic relationship by iPBS technique of 21 species and one variety of Clerodendrum L., two species of Rotheca Raf. and one species of Volkameria L. were conducted. Plant specimens were collected from wild population throughout the country during their flowering period in January 2015 to March 2017. Leaf anatomy was examined by paraffin technique, peeling method and scanning electron microscopic observation. Key to genera and speecies, the species descriptions and illustrations of leaf blade anatomical characteristic are given. The significant characteristics are pointed out and discussed. Briefly, Clerodendrum and Rotheca species have irregular epidermal cell with sinuous anticlinal wall and discontinuous cylindrical vascular bundle. Only Volkameria species has isodiametric cell with straight anticlinal wall and continuous arc-shaped vascular bundle. Stomatal types can be used to classify studied plants into two groups; anomocytic stomata occur in Clerodendrum and Volkameria, whereas diacytic stomata occur in Rotheca. Moreover, trichome types and presenced are significantly helpful to differentiate the three genera and some taxa in Clerodendrum. For the molecular study by iPBS, ten primers out of thirty successfully generated a total of 735 scorable bands in the 24 studied taxa and 734 bands are polymorphic (%99.9). The neighbour joining dendrogram (NJ) based on genetic similarity and principle coordinate analysis (PCoA) can separate plant into the groups which agree very well with the previous taxonomic studies using both morphological and molecular phyletic information. The results indicate that anatomical data and iPBS molecular marker provide taxonomic supportive evidence for the three genera and some species of Clerodendrum in Thailand.